I would repeat the test after measuring out the distance again. Rangefinders can be plus or minus a few yards just based on reflectivity/color of your target. In my experience, Euro RFs show this amount of error regularly. Based on the calculations provided by previous poster you are within the...
VX3, 4.5-14x40 1 inch main tube and no side focus. It is light and on all my carry rifles. you get one revolution on the dial and should get out to 650 or so on both your rifles.
Is it possible your rifle starts shooting right after it warms up? If I read your posts, it seems like you shoot 2 at 100 and then dial up with a slightly warmer barrel? Try starting your test at elevation and dial down. I saw a friend’s rifle do this consistently with his 3rd shot. 1.5”...